The present invention relates to a telecommunications network for mobile users, said telecommunications network for mobile users comprising a user's subsystem and a transport subsystem connected by means of an access subsystem, which offers them respectively a user access communications interface and a transport access communications interface (Iu), suitable to permit the exchange of the information flows (TS) among said subsystems, said access subsystem (AST) singling-out a coverage area of the cellular telephone network. Based on various analyses, it is expected that in a short time we will see a large increase in the quantity of information exchanged between users equipped with mobile radiotelephone terminals and the networks of the providers of such services. In light of such future needs, various national and international organizations (e.g. ITU, ETSI, FCC, etc.) dealing with regulations affecting radio frequencies allocation and utilization and the relative standards of data processing and signal modulation techniques, agreed on the definition of standards (or a group of standards like the GSM GPRS and the IMT 2000 or 3G) which allows a significant increase in the velocity of exchange between the mobile networks and the user mobile terminal and vice versa. The IMT 2000 group of standards, for example, includes the new standards called CDMA 2000 and Universal Mobile Telecommunications System (UMTS) or 3G (third generation) that allow video-conferencing and compatibility with the protocols of Internet networks (e.g., Ipv6) with other networks of the same family (e.g., DECT), and with the previous generation (2G) wireless telephone networks (e.g., GSM and PCS) and their improved data transport versions such as GPRS, EDGE, etc., (usually referred to as 2.5G). At the same time, new software and signal processing methodologies and standards are continuously developed in order to minimize the request for bandwidth for the digital broadcasting of Video Clips, TV programs and Audio programs and to allow the transmission of video, music, voice and images on digital networks such as Internet, Intranet and the like, and wireless cellular networks as well as wireless local area networks. In addition, all the technologies required to produce efficient and smart wireless mobile terminal at low cost are in constant and rapid development. These technologies contribute in the production of portable radio terminals capable of incorporating into the basic telephone function, various additional complex functions (graphic visualization with satisfactory resolution, functions typical of PCs, the capacity to interpret and elaborate various standards and protocols of the Internet field, storage of large quantities of data and management of serial interfaces, elaboration and reproduction of audio and visual files according to various standards, management of serial interfaces by modem, and infrared and radio interfaces for the exchange of data over short distances with other digital devices or network gateways, reception and processing of GPS signals, execution of complex interactive games, rapid decryption of files, voice recognition and synthesis, etc.).
It seems correct, then, to assume that the diffusion of new terminals capable of providing an efficient Internet connection, showing videos, graphics and of reproducing voice, music, and television file-data, also downloadable from the Internet, will result in a dramatic increase in the quantity of transmitted data in the terrestrial radio networks for mobile phones.
Therefore, in addition to the implementation of improved standards, in order to provide a qualitatively acceptable service to customers, the wireless network providers will be forced to continually increase their investment in upgrading their network capacities to meet the increasing data traffic demand.
A good example is the third generation (3G) of cellular networks, based on the UMTS standard, which are designed for multimedia communications. With these systems, personal communications can be improved with quality images and/or video and access to the information or services on public and private networks and can be improved by utilizing the highest data rate available and the highest communication flexibility for each system.
Such systems possess, among other things, the following characteristics:
Variable bit rate in order to furnish a wider bandwidth compatible with the service requested (from about 16 KBPS for voice communication to about 384 Kbps, and up to 2 Mbps for “High Multimedia” services);
Multiplexing services with different quality requirements in a single connection;
Quality requirements from 10% frame error to 10−6-bit error rate;
Compatibility with second-generation and 2.5 G systems (e.g., GSM handover intersystems for better coverage and traffic balance)
Support for asymmetric traffic for uplinks (from user to provider) and downlinks (from provider to user)
High efficiency in spectrum utilization
Compatibility of FDD (Frequency Division Duplex) and TDD (Time Division Duplex) connection modes.
Among the most important characteristics of the network based on the UMTS standard are the high user bit rate, compatibility with Internet standards, the capability to run multimedia files and the “always on” connection mode for the terminal.
It is logical to predict that initial use of the UMTS network will be constituted primarily of voice and Internet content while the amount of multimedia data traffic will increase later. Since the requested information will be primarily available on the Internet, it is important to implement efficient management of the TCP/UDP/IP traffic in the UMTS network. To be successful, the UMTS must be, therefore, capable of supporting a wide array of applications with different performance and quality service requirements.
The UMTS network at the level of network architecture, consists of a combination of logical network elements each with a specific functionality. In the context of standards, both the logical elements and the open interfaces among them are defined so that it is possible to automatically identify the network's physical elements as well.
The presence of open interfaces, in particular in the access network called UTRAN (UMTS Terrestrial Radio Access Network) in 3G standard, allows interconnection to the UMTS network as well to modes not explicitly envisioned by the current standards. For what concerns the detailed description of the services and performance standardized or in the course of definition for the mobile telephone networks 2.5G and 3G, please refer to the product documentation of the groups 3GPP and 3GPP2 (Third Generation Partnership Project and Third Generation Partnership Project 2) for which a synthesis is available in publications such as “WCDMA for UMTS” by Holma and Toskala, John Wiley & Sons, 2000, while in the enclosed FIG. 1, which is described below, some elements of the UMTS network, which are necessary in order to describe the invention, are shown.
FIG. 1 shows a diagram of the highest level architecture of a popular type of telecommunications network for UNET mobile users according to the UMTS standard that comprises three subsystems all three of which are interconnected: —user terminal subsystem (STU, which in the standard is indicated as User Equipment. This user terminal subsystem STU constitutes the user terminal system, that is, the portable terminal, such as for example a cellular phone. Said user terminal subsystem (STU) is interconnected to the telecommunications network for mobile users UNET and in particular to an access subsystem STA through a user access interface Uu by which data and voice TS signals are received and transmitted. This user access interface Uu, as previously mentioned, is an open type in order to allow operation in association with a greater number of terminal brands. The user terminal subsystem is comprised of a user ID module USIM, analogous to the so-called SIM card of the GSM standard, and a mobile equipment ME, that is the cellular phone hand set that communicates by means of a specially designed equipment interface Cu.
access subsystem STA: said access subsystem STA constitutes the network access for the UMTS standard, the above-mentioned UTRAN system and connects to a transport network STT through a transport access interface Iu.
transport subsystem STT: this transport subsystem, identified as Core Network in the UMTS standard, constitutes the transport network of the UMTS system. This transport subsystem, in addition to being interconnected by means of an transport/access interface Iu to the access subsystem STA, must be able to interconnect with all the other existing networks (external networks, PSTN, ISDN, B-ISDN, Internet, etc.), that are identified in FIG. 1 by means of the EXTNET block. Included in said transport subsystem STT are means for information management, routing and switching, which are typical of the wireless telephone networks including a Mobile Services Switching Center MSC, a Home Location Register HLR and a database Visitor Location Center VLR, an interconnection node or Gateway Mobile Switching Center GMSC, and a node for running the Serving GPRS Support Node SGSN or GGSN (Gateway GPRS Serving/Support Node).
In FIG. 1, it is possible to see, inside of the access subsystem STA, base stations SNB that correspond to the base stations as defined as Node B in the UMTS standard, such as the radio stations that broadcast over the area that identify the cells or system domains of the mobile phones. Their primary function consists of the exchange of the radio interface Uu with the data and voice signal TS with the user terminal subsystem STU. These base stations SNB carry out the management of the principal radio resources as, for example, the power.
Inside the access subsystem STA is included, among other things, a network radio controller CRR (called Radio Network Controller in the UMTS standard). This radio network controller CRR has complete control of all the radio resources of its domain, including all the base stations SNB connected to the CRR by means of dedicated controller-stations interface Iub.
The radio network controller CRR manages one or more base stations SNB, manages the setting of the radio channels (setup and release of the connections), the frequency hopping, the internal handovers and other functions, communicating with the transport subsystem STU, in particular with the switching center MSC. A great number of base stations SNB are present in large urban areas controlled by just a few radio network controllers CRR.
Due to predictable growth required by multimedia information exchange, the network UNET described in FIG. 1 will have to carry an increasing traffic, which from the external networks EXTNET must be transmitted bidirectionally across the transport/access interface Iu and the access/user interface Uu. As mentioned above, in order to furnish a service qualitatively acceptable to customers the managers of the UMTS networks and wireless networks in general, are forced to provide continued investments to match the capacity of the networks to the increasing demand. In addition, the demand for new services will call for additional resources dedicated to the planning, implementation and management of such new services, which will result in a further increase of implementation costs and time.